title: The risk of maternal and placental complications in pregnant women with asthma: a systematic review and meta-analysis.
abstract: OBJECTIVE
  To investigate if maternal asthma is associated with an increased risk of maternal and placental complications in pregnancy.
  
  
  METHODS
  Electronic databases were searched for the following terms: (asthma or wheeze) and (pregnan* or perinat* or obstet*). Cohort studies published between January 1975 and March 2012 were considered for inclusion. Forty publications met the inclusion criteria, reporting at least one maternal or placental complication in pregnant women with and without asthma. Relative risk (RR) with 95% confidence intervals (CIs) was calculated.
  
  
  RESULTS
  Maternal asthma was associated with a significantly increased risk of cesarean section (RR = 1.31, 95%CI = [1.22-1.39]), gestational diabetes (RR = 1.39, 95%CI = [1.17-1.66]), hemorrhage (antepartum: RR = 1.25, 95%CI = [1.10-1.42]; postpartum: RR = 1.29, 95%CI = [1.18-1.41]), placenta previa (RR = 1.23, 95%CI = [1.07-1.40]), placental abruption (RR = 1.29, 95%CI = [1.14-1.47]) and premature rupture of membranes (RR = 1.21, 95%CI = 1.07-1.37). Moderate to severe asthma significantly increased the risk of cesarean section (RR = 1.19, 95%CI = [1.09-1.31]) and gestational diabetes (RR = 1.19, 95%CI = [1.06-1.33]) compared to mild asthma. Bronchodilator use was associated with a significantly lowered risk of gestational diabetes (RR = 0.64, 95%CI = [0.57-0.72]).
  
  
  CONCLUSIONS
  Pregnant women with asthma are at increased risk of maternal and placental complications, and women with moderate/severe asthma may be at particular risk. Further studies are required to elucidate whether adequate control of asthma during pregnancy reduces these risks.
authors.affiliation: Centre for Asthma and Respiratory Diseases, University of Newcastle and Hunter Medical Research Institute , Newcastle, NSW , Australia .
authors.forename: Gang
authors.initials: G
authors.lastname: Wang
authors.forename: Vanessa E
authors.initials: VE
authors.lastname: Murphy
authors.forename: Jennifer
authors.initials: J
authors.lastname: Namazy
authors.forename: Heather
authors.initials: H
authors.lastname: Powell
authors.forename: Michael
authors.initials: M
authors.lastname: Schatz
authors.forename: Christina
authors.initials: C
authors.lastname: Chambers
authors.forename: John
authors.initials: J
authors.lastname: Attia
authors.forename: Peter G
authors.initials: PG
authors.lastname: Gibson
mesh_terms: D001249:Asthma / Q000150:complications* / Q000453:epidemiology / Q000628:therapy; D002585:Cesarean Section / Q000706:statistics & numerical data; D016640:Diabetes, Gestational / Q000453:epidemiology; D005260:Female; D006801:Humans; D010922:Placenta Diseases / Q000453:epidemiology / Q000209:etiology; D011247:Pregnancy; D011248:Pregnancy Complications / Q000453:epidemiology / Q000209:etiology* / Q000628:therapy; D011256:Pregnancy Outcome / Q000453:epidemiology; D012306:Risk
keywords: Asthma; maternal and placental complications; meta-analysis; pregnancy